Patent GB-622973-A (GB)
Title: Automatic arc welding machine
IPC: B23K9/12
Filed: 1947-02-12
Abstract: 622,973. Uniting by fusion. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. Feb. 12, 1947, No. 4044. Convention date, Feb. 15, 1946. [Class 83 (iv)] In an automatic arc-welding machine in which electrode holders are attached to an endless chain or strip running over a pair of chain or other wheels and receive electrodes fed successively from a magazine and jammed thereinto when they reach a predetermined position, the electrode next to the operating electrode rests with its upper end against a guide so that it enters an opening in the holder when the latter on its downward motion reaches a predetermined position, the lower end of the electrode being sustained by a support until it is pressed therefrom by continued downward motion of the holder. The welding head comprises a twopart casing 2, 3, Fig. 12, the parts of which are secured together by bolts 4 and are grooved at 7, 7a, Fig. 3, to guide electrode holders 15, Fig. 7, and electrode guides 28 carried by a chain 11 moving in grooves 12a in the part 2. In this form, the holders are rigidly fixed at one end to a chain link. The casing is slotted at one end for the introduction in turn into the grooves 7a of electrodes 19 which are mounted in line in a magazine secured to the casing, the magazine having an inclined bottom 38 with at one end a pair of bent leaf springs serving as a stop for the lower end of the foremost electrode. Each holder is provided with an opening 18, Fig. 10, to receive the upper end of this electrode and is slotted at 16 to accommodate a spring-controlled lever 17 for gripping the electrode and also for ejecting the unconsumed end thereof. The levers are operated to grip the electrode when the end 22 of the lever slides down a bevelled portion 24a of the groove 7a, the lever having a cut-away portion, one side of which grips the electrode and the other serves to eject the unconsumed end when the end 22 of the lever engages a second bevel 24, Fig. 3, in the groove 7a. The holders each carry a spring-pressed current conducting contact 27 for supplying current to the electrode from the casing. The electrodes are pressed against the welding head by a strip connected at one end to the head and led round the outer electrode and rolled up in a spring-operated box attached to the other side of the head. As the holder moves downwards to effect the weld, the next electrode rests in a groove 25 in the outer edge of the holder and in a groove 29 in the guide 28, the depth of which may be adjusted by a screw 30. At a predetermined position, the rear end of this electrode passes into the hole 18 in the holder and is pressed down and out of the magazine and along the side of the groove 25 in the leading holder. When such holder has reached its lowermost point, the lower end of the new electrode is close to the unconsumed portion of the previous electrode and when the holder turns the new electrode takes over the arc therefrom. Compressed air is delivered through a pipe 43 into the casing to keep out welding particles. The chain is traversed by a series electric motor supplied from a circuit, the voltage of which changes in dependence on the arc voltage so as to keep the length of the arc constant. The motor circuit contains an adjustable resistance. In a modification, Fig. 13, the holders 15 may be freely pivoted on the chain links so that in their lowest position they may slide over a yieldable member so that the lower end at the lower turning position may remain directed towards the welding point. The casing may have both sides straight as the holders do not require space for swinging. The unconsumed part of the electrode is ejected through an opening 50 in the casing, the opening being provided with a spring-controlled pivoted flap 51 which is moved aside by the holder to allow passage thereof. The head may be arranged in the reverse position for overhead welding, and in a horizontal position for welding on a vertical surface. The Specification as open to inspection under Sect. 91 states that the electrodes in the magazine may be pressed against the welding head by a spring-operated lever with a roll at the end. Also the guide 28 may be replaced by a stationary forked member moved to the side by a member attached to the chain. The forked member may be angularly adjusted to suit different diameters of electrodes. When welding in a horizontal position on a vertical surface, two spring-actuated flaps may be used to draw the unconsumed part out of the holder. In a modified machine the chain mechanism may be replaced by a toothed wheel reciprocating a pair of parallel racks in opposite directions, the racks each carrying an electrode holder and co-operating with a separate electrode magazine. This subject-matter does not appear in the Specification as accepted.